Car roof



Nov. 22, 1932. c. D. BONSALL CAR ROOF Filed Feb. 25, 1932 2 Sheets-Sheet a 5 A 1 Q /Nl/.6N:

M5 9170 2M5 Ks.

Nov. 22, 1932. c. D. BONSALL 1,888,901

H 5 Arm/21mm.

Patented Nov. 22, 1932 UNITED STATES PATENT OFFICE PENNSYLVANIA PENNSYLVANIA, ASSIGNOR TO P. H. PENNSYLVANIA, A CORPORATION OF CAR ROOF Application filed. February 25, 1932. Serial No. 595,107.

This invention relates to car roofs of the so-called neutral axis type wherein the roof sheets are adapted, arranged and secured together to form panels at one upper level alternating with panels at a lower level and connected by vertically disposed webs so as to be self supporting after the manner of a beam supported on the sides of the car. The theory of this type of roof is that the metal of the lower panels will take care of the tensile stresses and the metal of the upper panels will take care of the compressive stresses in the roof considered as a beam, the shearing stresses being taken by. the web portions that connect the upper and lower panels. On account of the thinness of the roof sheets, the eifective resistance of the metal of the upper panels to compressive stress decreases more and more, in comparison with the potential compressive strength of the metal, as the distance from the vertical webs increases, so that, when the span between vertical webs becomes wide, the middle portion of the upper panel becomes quite inefficient in resisting compression.

The principal object of the present invention is to devise means whereby wide upper panels may be used and still develop substantially the full compressive strength of the metal thereof. The invention consists principally in forming the upper panels by raising the side marginal portions of adjacent sheets and rigidly securing them together by a hollow box seam, whose vertically disposed sides are close enough to the respective webs of the roof structure to permit substantially the full compressive strength of the metal in the upper panel to be developed. It also consists in making the marginal portions of the sheets thicker than the intervening body portions to further increase the strength of the upper panels and the box seams. It also consists in the parts, and combinations of parts hereinafter described and claimed.

In the accompanying drawings wherein like reference numerals refer to like parts wherever they occur,

Fig. 1 is a plan view of a portion of a car roof embodying my invention,

Fig. 2 is a vertical transverse section through one-half of the roof, the section being taken through one of the lower panels on the line 22 in Fig. 1,

Fig. 3 is a similar section through one of the upper panels on the line 3-3 in Fig. 1,

Fig. 4; is a vertical longitudinal section on the line 4-.i in Fig. 1,

Fig. 5 is an enlarged vertical cross-section through one of the upper panels on the line 55 in Fig. 1,

Fig. 6 is a view similar to Fig. 4 showing a modified construction; and

Fig. 7 is an enlarged vertical cross-section through adjacent panels of the construction shown in Fig. 6.

According to the present invention the roof sheets 1 extend from side plate 2 to side plate 2 and are rigidly secured thereto. The roof sheets are also rigidly secured to each other along their side margins by rows of rivets 3. The sheets are adapted and arranged to form a series of alternating ribs A and channels B, that is, alternate sheets or panels thereof constituting panels 4 at a lower elevation alternating with panels 5 at a higher elevation and connected by vertical- 1y disposed webs 6. In the construction illustrated in Figs. 1 to 5, the longitudinal middle portion of the roof sheet constitutes the lower panel 1, and both sides of the sheet are offset upwardly being connected to the lower panel by the vertically disposed webs 6. Near the side edge of one side margin the sheet is formed, with an open top channel 7 of substantially the same depth as the webs '6. The plain marginal side of one of the sheets laps entirely across the channeled portion 7 of the marginal side ofthe adjacent sheet and is riveted thereto on opposite sides of the channel by the row of rivets 3, thus forming a hollow boX seam.

It is noted that the hollow box seam is located substantially midway between sides of the upper panel 5, that is, equidistant from the web members 6 that constitute the sides of the roof rib A. It is also noted that the hollow box seam not only greatly increases the strength in itself and develops the full compressive strength of the upper panel 5 di rectly above sald seam but also functions after the manner of the vertically disposed Webs 6 so as to develop the full compressive strength of the portion of the metal of said upper panel adjacent to the sides of said seam. Thus, with an upper panel of normal width substantially the full potential compressive strength of the metal may be developed because no portion thereof is so far from a vertical web portion as to be likely to fail by buckling without developing its compressive strength. As the purposes of the hollow channels 7 in the roof sheet are to form hollow box seams that reduce the span between the webs 6 of said ribs A, the width and depth of said ribs, as well as the width of the upper panels 5 and the thickness of the metal therein may be varied according to the plan of the designor. For instance, the strength of the upper panels and the box seams may be further increased by making the marginal portions of the sheets thicker than the intervening portions throughout a width sufiicient for forming the box seams. With this arrangement the lower panels, which are in tension, may be made wider than the upper panels. This thickening of the marginal portions of the sheets increases the effective life of the sheets, and it also prevents the rivets from tearing the sheets during the wearing of the car.

In the construction illustrated in Figs. 1 to 5 each sheet has one of its raised side margins plain and the other formed with the channel 7 therein.

In the modification shown in Fig. 6, the channels 7 are formed in both raised portions of the same sheets, in which case the adjacent sheets have both their raised side margins plain.

What I claim is:

1. A car roof comprising roof sheets secured together along their adjacent margins by hollow box seams, said roof comprising hollow ribs alternating with channels and said hollow box seams being located near the middle of the ribs.

2. A car roof comprising roof sheets secured together along their adjacent margins by hollow box seams, said roof comprising hollow ribs alternating with channels and said hollow box seams being located near the middle of the ribs between the tops of the ribs and the bottoms of the channels.

3. A car roof comprising roof sheets whose adjacent side margins are shaped and rigidly secured together to form hollow box seams, said roof comprising hollow ribs alternating with channels and said hollow box seams being located near the middle of the ribs.

4. A car roof comprising roof sheets whose adjacent side margins are shaped and rigidly secured together to form hollow box seams, said roof comprising hollow ribs alternating with channels and said hollow box seams being located near the middle of the ribs, between the tops of the ribs and the bottom of the channels.

5. A car roof comprising roof sheets whose adjacent side margins are shaped and rigidly secured together to form hollow box seams, said roof comprising hollow ribs alternating with channels and said hollow box seams being located near the middle of the ribs, the side marginal seam forming portions of said sheets being thicker than their body portions.

6. A car roof comprising roof sheets whose adjacent side margins are shaped and rigidly secured together to form hollow box seams, said roof comprising hollow ribs alternating with channels and said hollow box seams being located within said hollow ribs, the box seam forming portions of said sheets being thicker than the remaining portions of said sheets.

7 A car roof comprising hollow ribs alternating with channels, the metal in the tops of said ribs being thicker than the metal in the sides thereof.

8. A car roof comprising hollow ribs als;

ternating with channels, the metal along the middle portions of said ribs being thicker than the metal adjacent to the sides thereof.

9. A car roof comprising metal roof sheets whose side marginal portions are thicker than their body portion and shaped to form hollow box seams.

10. A car roof sheet having side marginal portions of greater thickness than the body portion thereof, one of said thickened marginal portions having a channel formed therein and the other thickened marginal portion being left plain.

Signed at St. Louis, Mo, this 26 day of January, 1932.

CHARLES DAVID BONSALL. 

